Unlike methods and classes, lambdas lack names and documentation; if a computation isn’t self-explanatory, or exceeds a few lines, don’t put it in a lambda.
One of the biggest issues I see in functional programming. If the lambda is not a trivial operation then it deserves its own method. Just because most functional examples use lambdas as part of map(), fold(), etc doesn't mean you should if it's not immediately obvious what the lambda is doing
